(1 of )The passageway on East Napa St. known as Vine Alley, which hosts the greatest concentration of tasting rooms on the Plaza. (Photo by Robbi Pengelly/Index-Tribune)

Many Sonoma residents have noticed the metamorphosis of storefronts around Sonoma Plaza and intersecting side streets from local retail shops to tasting rooms and wine bars.

What has brought about this change?

Lots of factors. Perhaps first and foremost is the Sonoma’s burgeoning reputation as a wine-tourism destination. Many print publications, blogs and online media site the city as a great place to visit and vacation, creating interest in locating a business here, driving up rents and pricing out some of the small local businesses.

Some wineries are better able to afford the rents. And many winery owners seek high-traffic areas, such as the Sonoma Plaza, to place their tasting rooms — especially when their winery headquarters are located away from the shopping crowds.

It’s a mistake if we call all tasting rooms “wine bars,” because technically most are not.

There are three kinds of California ABC licenses that businesses might need to pour wine. Type 02 is for wine growers who make wine. Wineries that make wine in another winery’s facility qualify, as well.

Wineries whose wine is “custom crushed” for them need a Type 17/20 license, which means, according to the North Bay Business Journal, they are licensed as a wholesaler of wine with limited retail privileges and cannot open a tasting room of their own.

A Type 41 license allows for restaurants/eating places to serve wine and beer.

Type 42 regulates beer and wine in bar or tavern settings.

Altogether, Sonoma has 28 Type 02 “tasting rooms” around Sonoma Plaza, as well as some Type 41s and 42s. Here’s a quick list, with out-of-Sonoma ownership indicated when applicable.

On First Street West north of Spain Street, tasters will find wine to sip at Auteur, Hawkes (Healdsburg), and Walt (Mendocino and Napa), with Roche and Three Sticks tasting rooms just off the Plaza. Between Spain and Napa streets are Lake Sonoma Winery (Valley of the Moon and Madrone Vineyards), and Rancho Maria (Healdsburg). Jayme Powers is moving her Sigh Champagne and sparkling wine to the first block of West Napa Street, with Corner 103 at the corner of West Napa and First Street West. Jeff Cohn (Oakland) is opening a tasting room on First Street West across the breezeway from the Red Grape, with Winery Sixteen 600 down the street.

Bordering or on Broadway, tasters will find Bump, Enkidu, and Roger Roessler; Adastra on Napa Street; and Westwood, MacLaren, Passagio, Fulcrum (Sonoma Coast) replacing Sigh in “Vine Alley.” The Galatea Effect (Tempe, Arizona), Sonoma-Loeb (Napa/Sonoma) and the new Cochon (Napa) are down First Street East.